1. Field of the Invention
Apparatuses and methods the present invention relate to preventing an error in an information processor such as a computer, a personal digital assistant (PDA), and a cellular phone, and more particularly, to verifying whether an instruction of a computer program is invalid due to a virus or hacking, when a central processing unit (CPU) embedded in the information processor executes the instruction of the computer program.
2. Description of Related Art
According to a related art technique for protecting against computer virus, samples of a computer virus, which have previously occurred, are collected, specific character strings that can be a characteristic feature of the computer virus are extracted, and whether a computer file is infected by the computer virus is verified by determining whether the specific character strings exist in the computer file.
Accordingly, once a new computer virus occurs, identification of the new computer virus is required to be acquired, character strings that may be a characteristic feature of the new virus are is required to be extracted, and a vaccine program corresponding to the new computer virus is required to be developed. Thus, protection against the new computer virus is impossible, and damage from the new computer virus cannot be prevented until after information about the new computer virus is added to a related art vaccine program. As types of a computer virus are increased, types of character strings that can be a feature of the computer virus are increased, and therefore a required time to verify whether the character string exists is increased.
When a computer receives a control flow attack from a hacker, the hacker inputs a code for executing a hacker's program into a specific address by making use of a weakness of a computer. While a general program is executed, the computer under the control flow attack branches to an address storing an instruction of the code to start the hacker's program and executes the hacker's program, the hacker thereby manipulates the computer under the control flow attack for the hacker's own purpose.
According to the related art, when the weakness of the computer program is disclosed due to the hacker's attack, a company developing the computer program can protect against the hacker's attack using a patch program having rectifying the weakness, however there is no solution against other attacks using other weaknesses which are not disclosed.